1. The Field of the Invention
This invention relates generally to touchpads and mobile telephones. Specifically, the invention relates to adapting a touchpad so that it can be disposed and operated while underneath a keypad of a mobile telephone, wherein the user operates the keypad by pressing keys on a keymat in a typical manner, and wherein the touchpad disposed underneath the keymat can be activated to thereby enable manipulation of a display in the mobile telephone so as to control a cursor, scroll bars, and alphanumerical data entry in the mobile telephone.
2. Background of the Invention
Portable information appliances include portable communication devices known by many popular names such as cellular telephones, cell phones, and mobile telephones (hereinafter referred to collectively as “mobile telephones”) to name a few. Mobile telephones are now capable of providing more services than just voice transmission. For example, mobile telephones now provide data services such as access to the Internet for web browsing and for using email. These services are becoming ubiquitous as the infrastructure to provide them is becoming more widely available.
There are several problems that inhibit use of these data services. Because these mobile telephones are small devices, there is a lack of surface space on them in which to implement data entry and display control technologies. A mobile telephone must typically rely on the keypad as the main source of alphanumerical data input and display control. Unfortunately, experience has shown that using the keypad for all types of data entry and display control is inefficient, slow, cumbersome, and frustrating to the user. Thus, while the ability to easily navigate a graphical interface such as a mobile telephone web browser and to rapidly enter text in a word processor in order to send email is highly desirable, it is unfulfilled.
It would therefore be an advantage over the prior art to provide a system that enables both rapid data entry and graphical display control in a portable information appliance, such as the mobile telephone. Ideally, the system should enable the mobile telephone to retain its conventional keypad, while providing a touchpad and the associated touchpad capabilities. However, the system should not require a separate touchpad surface. Thus, the system should incorporate a touchpad without modifying the appearance of the mobile phone. The touchpad could be disposed underneath the keymat and be actuated by a switch or other means of activation.
Alternatively, the touchpad could be disposed underneath a display screen, or underneath some portion of the body of the mobile telephone where a user can run a finger over a surface thereof. What is important is that the touchpad operate through proximity sensing, and thus not require direct contact with the touchpad in order to operate. The surface through which the touchpad could detect a pointing object could be the keymat of the keypad, an LCD display screen, or a portion of the body of the portable information appliance that is easily accessible by touch.